Method of maritime delivery of crude oil through ice-congested regions

ABSTRACT

Method of maritime delivery of crude oil through ice-congested regions, for example, from the North Slope of Alaska through the Northwest Passage, including driving an icebreaker vessel with crude oil load through the ice-congested region, pumping crude oil from said icebreaker vessel into a floating oil storage terminal maintained at the far edge of the ice-congested region, offloading crude oil from within the storage terminal into a tanker, and driving the tanker to an ice-free oil terminal facility. A modification of invention includes loading of the crude oil at the North Slope into a submarine vessel which is driven beneath the ice pack to the floating oil storage terminal at the far edge of the ice pack.

United States Patent I Deal, Jr. et al.

[451 July4, 1972 [54] METHOD OF MARITIME DELIVERY OF CRUDE OIL THROUGH ICE- CONGESTED REGIONS [72] Inventors: Joseph D. Deal, Jr.; James C. Michie, III,

both of Newport News, Va.

[73] Assignee:

Company, Newport News, Va.

22 Filed: April 13, 1971 21 Appl.No.: 133,578

[52] US. Cl ..l37/l, 114/5, 137/236 [51] Int. Cl ..B63b 27/00 [58] Field ofSearch ..l37/1; 114/.5 T, 93.5,45;

[56] References Cited UNITED STATES PATENTS 3,018,748 l/l962 Denis ..ll4/74 Newport News Shipbuilding and Dry Dock 1 3,408,97l 7/1965 Mott ..1l4/.5T

Primary ExaminerAlan Cohan Att0rneyDavid H. Semmes [57] ABSTRACT Method of maritime delivery of crude oil through ice-congested regions, for example, from the North Slope of Alaska through the Northwest Passage, including driving an icebreaker vessel with crude oil load through the ice-congested region, pumping crude oil from said icebreaker vessel into a floating oil storage terminal maintained at the far edge of the ice-congested region, offloading crude oil from within the storage terminal into a tanker, and driving the tanker to an ice-free oil terminal facility. A modification of invention includes loading of the crude oil at the North Slope into a submarine vessel which is driven beneath the ice pack -to the floating oil storageterminal at the far edge of the ice pack.

17 Claims, 9 Drawing Figures PATENTEUJUL 4 1972' 3,674,042

SHEET 1 or 3 1NVENTOR5 BY pad/2 M ATTORNEY PATENTEDJUL 41972 3.674.042

sum aur a ATTORNEY CROSS-REFERENCE TO RELATED APPLICATIONS None.

BACKGROUND OF THE INVENTION 1. Field of the Invention A plurality of Alaskan oil transport schemes have been occasioned by the Prudhoe Bay discoveries and leases of the Alaskan oil. With the exception of the Mackenzie River pipeline and the proposed Trans Alaska Pipeline System (TAPS), each of the proposed routes has involved a sea-leg component wherein an ice-breaking tanker, such as the Manhattan is utilized to carry crude oil directly through the Northwest Passage icepack to an ice-free port on the East Coast of the United States.

Ice-breaking tankers are expensive to manufacture and maintain and are relatively inefficient in open water. Hence, applicants have attacked the problem of utilizing an ice-breaking tanker or submersible vessel to its most economic benefit.

2. Description of the Prior Art Prior art investigation has been conducted in the following classes:

Class 6 hydraulic and earth engineering Subclass 64 dry dock Class 1 l4 ships Subclass 0.5 miscellaneous Subclass 43.5 mother ships, floating landing platfomis,

and harbors Subclass 44 vessel raising and docking Subclass 45 floating dry docks Subclass 46 sectional floating dry docks The following pertinent U.S. Pats. have been developed:

Nelson, No. 2,408,871

Chow, No. 3,507,238

Nelson relates to a floating dry dock, having ship repair and servicing facilities. There is no suggestion of crude oil storage capacity Chow discloses a semi-submersible oil storage vessel which may be used to store oil from off-shore production vessels prior to delivery to conventional tankers.

The prior art does not suggest the combination of a floating repair and oil storage vessel nor the use of such vessel in combination with an icebreaker or submarine in transporting crude oil through the Northwest Passage.

SUMMARY OF THE INVENTION According to applicants invention, crude oil is loaded onto an icebreaker vessel at a North Slope terminal, the icebreaker vessel is driven through the Northwest Passage ice pack, crude oil is pumped from the icebreaker vessel into a floating oil storage terminal at the far edge of the ice pack, then offloaded from within the storage vessel into a tanker which is driven to an ice-free East Cost oil terminal facility. The method includes dry docking of the icebreaker vessel for repairs at the same time as or subsequent to pumping of crude oil into the storage terminal. Alternatively, a submarine vessel may be loaded on the North Slope and driven beneath the ice pack to the floating oil storage terminal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a proposed floating repair and oil storage terminal facility, utilized according to the present method;

FIG. 2 is a schematic illustration of an all icebreaker tanker route from the North Slope through the Northwest Passage to an East Coast port;

FIG. 3 is a schematic view showing ice concentration in the Northwest Passage;

FIG. 4 is a schematic illustration of the present method, involving a transfer from the icebreaker to a conventional tanker vessel, using a floating repair and oil storage terminal, seasonally maintained at the edge of the icepack;

FIG. 5 is a schematic illustration of repositioning the floating repair and oil storage terminal, according to seasonal movement of the icepack;

FIG. 6 is a top plan of a proposed vessel according to the present method;

FIG. 7 is a side elevation;

FIG. 8 is a rear elevation with the stern wall gate removed; and

FIG. 9 is a legend showing the proposed floating repair and oil storage terminal vessel characteristics.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a proposed floating repair and oil storage terminal 10, utilizable according to the present method, is illustrated as having rounded bow l2 and reciprocable gate 14 in its stem wall. Helicopter pads 16 and 18 may be provided in the bow. The deck is of a substantial U-shaped configuration defining with the stern wall an open dry dock portion 30. Deck houses 20 and 22 may be supported on either side, raised bridge 24 being mounted at the forward portion of deck house 22. By way of example, a 30 ton whirler crane 26 and a 60 ton whirler crane 28 may be employed. A similar oil storage terminal is shown in FIG. 8 with an icebreaking or like vessel dry docked therein for repair. The tenninal may include outboard crude oil tanks 32 and 34 with median ballasting tanks 36 and 38. The suggested characteristics of such a terminal vessel are set forth in FIG. 9.

In FIGS. 2 through 5, there are illustrated, respectively, the all icebreaker tanker route from the North Slope to East Coast ports, the icepack concentration in the Northwest Passage, the present method of driving the crude via icebreaker to a floating repair and oil storage terminal, and transferring the crude to a conventional tanker. The floating terminal may be moved seasonally along the dotted lines so as to be maintained, at the edge of the icepack.

It is estimated that oil companies on the North Slope are losing millions of ROI dollars every month of delay in initiating construction of a viable transportation scheme for moving the oil to the Lower 48. A sea route through the Northwest Passage could be in operation in 1974. However, the Northwest Passage route is severely handicapped by the continuous old ice in Viscount Melville Sound and the Prince of Wales Strait. Where a large icebreaker tanker could average seven to ten knots in the new ice of Baffin Bay, as little as l knot could be expected through parts of the old ice. The economics of the icebreaker system are very sensitive to the average speed through the ice, and current speed estimates practically double the early expected transportation costs by this method.

Since the icebreaker tanker is a very expensive element of the system, methods for higher utilization of the icebreaker ship resulting in more voyages per year and less ships required to carry a fixed quantity of oil have been applicants key objective. The development of a floating terminal which could move with the seasonal extremes of the Baflin Bay ice grew from the realization that the expensive, highly specialized icebreaker tanker could not operate economically in open water. With a terminal constantly on the edge of the icepack, the icebreaker could spend practically all of its operational time in the ice. This was the basis for the present method, involving a floating repair and oil storage terminal (FROST).

FROST, as proposed by applicants, will not only increase the icebreakers productivity by shortening its average voyage distance, but will also add 15 days per year of operating time by providing on-station docking and maintenance for the icebreaker. The leg from FROST to the US. East Coast will be made by conventional tankers, such as a 120,000 DWT tanker.

Having evaluated the effect of FROST on the icebreaker system, its effect on the economics of the even more expensive submarine method was determined. Here again, FROST would be used for on-station docking and maintenance, and conventional tankers would be used for the East Coast leg. This combination system was evaluated against another proposed system of transferring crude oil at a sourthern Greenland terminal and was found to be economically superi- FROST is capable of docking and making both minor and major repairs with the use of its own shops and crew to either the icebreakers or the submarines or the conventional tankers. To save docking time, FROST was designed to dock and undock a fully loaded icebreaker and accomplish ballasting up and offloading oil simultaneously. FROST was also designed to include tankage for crude oil storage of 606,000 tons to minimize the criticality of rendevous scheduling.

The use of conventional tankers in moving the crude oil to the East Coast would allow a good distribution of the oil without extensive additional coastwise distribution because the conventional tankers have no constraints on entering the major U.S. East Coast ports. Conversely, the icebreaker would require a deep-water terminal and extensive auxiliary transport by pipeline or small coastal tankers to move the oil to the refineries.

Probably the most favorable aspect of FROST is that it reduces the investment risk of the Northwest Passage route for Alaskan oil for many reasons. It is estimated that this method for delivery of crude oil is 160 million dollars cheaper for the icebreakers and 626 million dollars cheaper for the submarines in acquisition cost for a 2 million barrels of oil per day system when compared to using icebreakers only and submarines with transhipment at Greenland; the conventional tankers (assumed as 120,000 DWT) can be used competitively on many routes; the floating repair and oil storage terminal itself could be used as a construction or repair facility practically anywhere; and the investment in highly specialized icebreakers and the submarines is 21 percent and '19 percent lower, respectively, than the investment required in an all icebreaker or all submarine system.

To maximize return on investments already made on the North Slope, as well as to meet the rapidly growing oil demand in the Lower 48, applicants method would bring the steady state transportation capacity to 2 million barrels of oil per day 2 years earlier for the icebreaker system and 1 year earlier for the submarine system.

The shorter round trip distance resulting from the use of applicants method would allow conversion in the current icebreaker design (proposed for use without FROST) of about 2,000 deadweight tons of required fuel oil to extra cargo capacity. Another possible addition of cargo capacity and considerable savings in original cost could be gained by eliminating the cargo pumps and pump rooms onboard the ship and supplying the terminal with high capacity deep submergence pumps.

The foregoing analyses were based on an incremental buildup to 2 million barrels of oil per day, and a considerable spread in required cost per barrel of oil delivered was evident between the four systems examined. The all-icebreaker system was found to be the most expensive; the icebreaker/FROST/conventional tanker system was 5 percent less; the all-submarine system was 26 percent less; and the submarine/FROST/conventional tanker system was 32 percent less. it should be noted, however, that the submarine systems, though cheaper, are a much higher risk due to the advanced technology required. Estimated delivery costs are set forth below.

OIL TRANSPORTATlON COST TO EAST COAST Submarines/conventional tankers 0.69

In summary, it is pointed out that:

FROST is a lower risk system. FROST goes steady-state 2 years earlier. FROST is 5 per cent cheaper for an icebreaker system. FROST is 8 per cent cheaper for a submarine system.

We claim:

1. Method of maritime delivery of crude oil through icecongested regions, comprising:

A. loading an icebreaker vessel with crude oil;

B. driving said icebreaker vessel with its crude oil load through said ice-congested region;

C. pumping crude oil from said icebreaker vessel into a floating oil storage terminal at the far edge of said icecongested region;

D. offloading crude oil from within said storage tenninal into a tanker; and

E. driving said tanker to an ice-free oil terminal facility.

2. Method for maritime delivery of crude oil through icecongested regions as in claim 1, including loading said icebreaker vessel at the near edge of an ice-congested area.

3. Method for maritime delivery of crude oil through icecongested regions, as in claim 1, including:

F. seasonally moving said floating oil terminal, according as said ice-congested region recedes and advances, such that said vessel is floating at the edge of said ice-congested region.

4. Method of maritime delivery of crude oil through icecongested regions, as in claim 3, including:

G. deballasting and ballasting said floating oil terminal dur ing said offloading of crude oil.

5. Method of maritime delivery of crude oil through icecongested regions, as in claim 4, including:

H. docking said icebreaker vessel within said floating oil storage terminal prior to said pumping.

6. Method of maritime delivery of crude oil through icecongested regions, as in claim 3, including pumping crude oil from a plurality of icebreaker vessels into said oil storage terminal prior to said offloading.

7. Method of maritime delivery of crude oil through icecongested regions, comprising:

A. loading a submarine vessel with crude oil;

B. driving said submarine vessel with its crude oil load beneath said ice-congested region;

C. pumping crude oil from said submarine vessel into a floating oil storage terminal at the far edge of said icecongested region;

D. ofiloading crude oil from within said storage terminal into a tanker; and

E. driving said tanker to an ice-free oil terminal facility.

8. Method for maritime delivery of crude oil through icecongested regions, as in claim 7, including:

F. seasonally moving said floating oil terminal, according as said ice-congested region recedes and advances, such that said vessel is floating at the edge of said ice-congested regron.

9. Method of maritime delivery of crude oil through icecongested regions, as in claim 8, including:

G. deballasting and ballasting said floating oil terminal during said offloading of crude oil.

10. Method of maritime delivery of crude oil through icecongested regions, as in claim 9, including:

H. docking said submarine within said floating oil storage terminal prior to said pumping.

11. Method of maritime delivery of crude oil through icecongested regions, as in claim 10, including:

1. pumping oil from a plurality of submarine vessels into said oil storage terminal prior to said offloading.

12. Method of maritime delivery of crude oil through icecongested regions, as in claim 5, including:

J. dry docking said icebreaker vessel for repair within said oil storage facility.

13. Method of maritime delivery of crude oil through icecongested regions, as in claim 7, including:

K. dry docking said submarine for repair within said oil storage facility.

14. Method of maritime delivery of crude oil through icecongested regions, as in claim 1, wherein said loading of said icebreaker is on the North Slope of Alaska; said driving of said icebreaker vessel with its crude oil load is through the ice-congested Northwest Passage; and said pumping of crude oil from said vessel is within Baffin Bay.

15. Method of maritime delivery of crude oil through icecongested regions, as in claim 14, wherein said driving of said tanker from the FROST oil storage terminal to the ice-free East Coast oil terminal facility is over a greater distance than said driving of said icebreaker vessel through the ice-congested region.

16. Method of maritime delivery of crude oil through icecongested regions, as in claim 7, wherein said loading of said submarine vessel is on the North Slope of Alaska; said driving of said submarine vessel with its crude oil load is through the ice-congested Northwest Passage; and said pumping of crude oil from said vessel is within Bafiin Bay.

17. Method of maritime delivery of crude oil through icecongested regions, as in claim 16, wherein said driving of said tanker from the FROST oil storage terminal to the ice-free East Coast oil terminal facility is over a greater distance than said driving of said submarine vessel through the ice-congested region. 

1. Method of maritime delivery of crude oil through icecongested regions, comprising: A. loading an icebreaker vessel with crude oil; B. driving said icebreaker vessel with its crude oil load through said ice-congested region; C. pumping crude oil from said icebreaker vessel into a floating oil storage terminal at the far edge of said ice-congested region; D. offloading crude oil from within said storage terminal into a tanker; and E. driving said tanker to an ice-free oil terminal facility.
 2. Method for maritime delivery of crude oil through ice-congested regions as in claim 1, including loading said icebreaker vessel at the near edge of an ice-congested area.
 3. Method for maritime delivery of crude oil through ice-congested regions, as in claim 1, including: F. seasonally moving said floating oil terminal, according as said ice-congested region recedes and advances, such that said vessel is floating at the edge of said ice-congested region.
 4. Method of maritime delivery of crude oil through ice-congested regions, as in claim 3, including: G. deballasting and ballasting said floating oil terminal during said offloading of crude oil.
 5. Method of maritime delivery of crude oil through ice-congested regions, as in claim 4, including: H. docking said icebreaker vessel within said floating oil storage terminal prior to said pumping.
 6. Method of maritime delivery of crude oil through ice-congested regions, as in claim 3, including pumping crude oil from a plurality of icebreaker vessels into said oil storage terminal prior to said offloading.
 7. Method of maritime delivery of crude oil through ice-congested regions, comprising: A. loading a submarine vessel with crude oil; B. driving said submarine vessel with its crude oil load beneath said ice-congested region; C. pumping crude oil from said submarine vessel into a floating oil storage terminal at the far edge of said ice-congested region; D. offloading crude oil from within said storage terminal into a tanker; and E. driving said tanker to an ice-free oil terminal facility.
 8. Method for maritime delivery of crude oil through ice-congested regions, as in claim 7, including: F. seasonally moving said floating oil terminal, according as said ice-congested region recedes and advances, such that said vessel is floating at the edge of said ice-congested region.
 9. Method of maritime delivery of crude oil through ice-congested regions, as in claim 8, including: G. deballasting and ballasting said floating oil terminal during said offloading of crude oil.
 10. Method of maritime delivery of crude oil through ice-congested regions, as in claim 9, including: H. docking said submarine within said floating oil storage terminal prior to said pumping.
 11. Method of maritime delivery of crude oil through ice-congested rEgions, as in claim 10, including: I. pumping oil from a plurality of submarine vessels into said oil storage terminal prior to said offloading.
 12. Method of maritime delivery of crude oil through ice-congested regions, as in claim 5, including: J. dry docking said icebreaker vessel for repair within said oil storage facility.
 13. Method of maritime delivery of crude oil through ice-congested regions, as in claim 7, including: K. dry docking said submarine for repair within said oil storage facility.
 14. Method of maritime delivery of crude oil through ice-congested regions, as in claim 1, wherein said loading of said icebreaker is on the North Slope of Alaska; said driving of said icebreaker vessel with its crude oil load is through the ice-congested Northwest Passage; and said pumping of crude oil from said vessel is within Baffin Bay.
 15. Method of maritime delivery of crude oil through ice-congested regions, as in claim 14, wherein said driving of said tanker from the FROST oil storage terminal to the ice-free East Coast oil terminal facility is over a greater distance than said driving of said icebreaker vessel through the ice-congested region.
 16. Method of maritime delivery of crude oil through ice-congested regions, as in claim 7, wherein said loading of said submarine vessel is on the North Slope of Alaska; said driving of said submarine vessel with its crude oil load is through the ice-congested Northwest Passage; and said pumping of crude oil from said vessel is within Baffin Bay.
 17. Method of maritime delivery of crude oil through ice-congested regions, as in claim 16, wherein said driving of said tanker from the FROST oil storage terminal to the ice-free East Coast oil terminal facility is over a greater distance than said driving of said submarine vessel through the ice-congested region. 